CVE-2026-58517: Improper neutralization of input terminators vulnerability in The Wikimedia Foundation Mediawiki - WikiLambda

Routine

MEDIUM 4.3UPGRADE

CVE-2026-58517 is a medium-severity flaw (CVSS 4.3) affecting mediawiki. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper neutralization of input terminators vulnerability in The Wikimedia Foundation Mediawiki - WikiLambda Extension allows Authentication Bypass. This issue affects Mediawiki - WikiLambda Extension: from * before 1.43.9,1.44.6,1.45.4.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 74%)
CISA exploited list	No
Weakness	CWE-288
Published	2026-07-01
Last modified	2026-10-25

Publisher (CNA): wikimedia-foundation · Vendor: mediawiki

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-01 19:16 UTCPublished CVE record published
2026-10-25 16:10 UTCUpdated Record last modified

mediawiki mediawiki UPGRADE

Affected: >= 1.43.0 and < 1.43.9 · >= 1.44.0 and < 1.44.6 · >= 1.45.0 and < 1.45.4

Fixed in: 1.43.9, 1.44.6, 1.45.4

Safe to downgrade to: a release before 1.43.0

1. Check installed version

apt-cache policy mediawiki || rpm -q mediawiki || mediawiki --version

2. UPGRADE to 1.43.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mediawiki

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mediawiki

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.43.0 (Debian / Ubuntu)

apt-cache madison mediawiki sudo apt install mediawiki=<VERSION_BEFORE_1.43.0> sudo apt-mark hold mediawiki

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mediawiki sudo dnf downgrade mediawiki-<VERSION_BEFORE_1.43.0> sudo dnf versionlock add mediawiki

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-58517?

mediawiki: upgrade to 1.43.9, 1.44.6, 1.45.4. Exact commands for each OS are on this page.

Is CVE-2026-58517 being exploited?

CVE-2026-58517 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-58517 affect?

CVE-2026-58517 affects mediawiki. Severity is medium (CVSS 4.3). Improper neutralization of input terminators vulnerability in The Wikimedia Foundation Mediawiki - WikiLambda Extension allows Authentication Bypass. This issue affects Mediawiki - WikiLambda Extension: from * before 1.43.9,1.44.6,1.45.4.

How urgent is CVE-2026-58517?

Priority 22/100. No elevated risk signals yet.

Related CVEs

CVE-2026-8857 HIGH 8.8 UPGRADE A vulnerability in Wikimedia Foundation timeline. This vulnerability is associated with program files script
CVE-2026-58025 CRITICAL 9.8 UPGRADE Deserialization of untrusted data vulnerability in Wikimedia Foundation MediaWiki. This vulnerability is ass
CVE-2026-13706 HIGH 8.8 UPGRADE Improper input validation vulnerability in Wikimedia Foundation UrlShortener. This vulnerability is associat
CVE-2026-58036 HIGH 7.5 DOWNGRADE Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation MediaWiki.
CVE-2026-58029 MEDIUM 6.5 UPGRADE Vulnerability in Wikimedia Foundation MediaWiki. This vulnerability is associated with program files include

References

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